1. Field of the Invention
This invention relates to a holder for a vane of a vertical venetian blind assembly used, for instance, for covering an architectural opening, such as a window or door.
2. Description of the Related Art
Vertical venetian blinds have generally been provided with horizontally-extending head rails, holding a plurality of carriers or travellers that can be moved in spaced apart relationship along the longitudinal length of each head rail. Each carrier has typically supported a vertically-extending louver, slat or vane by a vane holder in such a manner that the consumer of the venetian blind could move the vane along the length of the head rail (e.g. by pulling on a first operating cord or pull cord) and also could rotate or tilt the vane about its vertical axis (e.g. by pulling on a second operating cord or tilt cord). For this purpose, each carrier has typically included a main body with a vertically oriented drive hub or worm wheel, drivingly connected to a horizontally oriented worm gear. The bottom of each drive hub has supported a depending vane holder, adapted to hold securely the top of a vane while its carrier has been moved longitudinally and while the drive hub has been rotated so as to move the vane holder and the vane and tilt them about their common vertical axis. In this regard, a longitudinally-extending tilt rod or drive shaft has been provided in the head rail, extending through the carriers and engaging their worm gears, whereby rotation of the tilt rod about its longitudinal axis has caused the drive hubs of the carriers to rotate about their vertical axes so as to make the vane holders and the attached vanes tilt together.
A problem in mounting a vertical venetian blind in a slanted or sloped architectural opening is that, for each slope angle, different vane holders are required. Specifically, a suitable length for the holder has to be chosen for each related slope under which the blind is mounted, since the length of the vane holder influences the space the vane of the blind has for rotating and thus tilting. When the holder is too short, the upper marginal portion of the vane hits the head rail when rotated. When the holder is too long, it negatively affects the look of the blind. The steeper the slope, the longer the holder has to be. Generally, a blind manufacturer will offer a limited number of different length holders, each having a specific length and use for a specific number of slopes. So each holder of a specific length will be used for a range of slope angles. This is not ideal and will lower the quality of a blind product since it will not always be possible to have holders of the specific length necessary for a desired slope. The same problem occurs with curved mountings.
U.S. Pat. No. 6,000,456 solves a similar problem, based on a difficulty that can be encountered when mounting a vertical blind assembly adjacent an architectural opening. In particular, where the vanes of the vertical blind assembly are of a particular length, it is necessary that the head rail is positioned and mounted accurately relative to the architectural opening. If the head rail is mounted too high or too low, it becomes necessary to remount it, possibly causing undesirable damage to the architectural opening surrounding. As a solution to this problem, U.S. Pat. No. 6,000,456 proposes a vane holder having an adjustable length. The holder has a vane clasp and a clasp holder, the vane clasp having a first end, to which the vane of the blind is attached, and a second end which can be attached to the clasp holder. The holder, in turn, can be attached to a carrier of a vertical blind. The second end of the clasp has ratchet grooves, each of which can cooperate with a single locking tooth in the holder, such that a resilient ratchet-type mechanism is created. The clasp can be moved resiliently between engaging consecutively one of the securing points or ratchet grooves to the locking tooth in the holder so as to vary the height of the vane.
The adjustable length vane holders of U.S. Pat. No. 6,000,456 could, in theory, be used to solve the problem of sloped vertical blinds. Unfortunately, this is not the case since such holders were designed only for correcting small inconvenient differences in length. Furthermore, the connection between the vane clasp and the clasp holder is a single point connection, which is not a very reliable connection. In order to make the connection of the single locking tooth and the ratchet grooves more secure, the profile or depth of the locking tooth would have to be substantial. However, this would prevent adjustment of the vane holder of U.S. Pat. No. 6,000,456, which is a ratchet mechanism. Moreover, this would still not provide a really secure connection because of its single point of connection.